How to Do Discount Math Problems

A discount is an amount taken off the original price, which gives the buyer a better deal. Discounts are usually listed as a percent off -- such as 35 percent off -- or as a fraction off, such as 1/3 off the original price.

Calculating a Percent Discount

To find a percent discount, first change the percent discounted to a decimal by dividing the percent by 100. This means that 25 percent in decimal form becomes 0.25. Then, multiply the decimal by the original price. To illustrate this principle, here is an example: to find 25 percent of $36.00, multiply the decimal 0.25 by 36 to equal 9, which represents $9. This $9 is the amount to discount or take off the original. To find the discounted price, subtract the $9 discount from the original price, so that you subtract nine from 36, as you see here: 36 - 9 = 27. The discounted price is $27.00.

Calculating a Fraction Discount

To find the fraction off the original price, first divide the original price by the denominator, which is the bottom numeral of the fraction. Then, multiply the quotient by the numerator, which is the top numeral in the fraction. The number that results is the discount. To get the discounted price, subtract the discount from the original price. To illustrate this principle, here is an example: to take 1/3 off $36.00, divide 36 by 3 and multiply by 1. This becomes 36/3 x 1 to equal 12, which represents a discount of $12.00. To get the actual discounted price, subtract 12 from 36, in other words, 36 minus 12 to equal 24. The discounted price is $24.00.